Methacrylic Acid Sodium Salt Research Articles

Poly Methacrylic Acid Sodium Salt (PMANa)/Polyurethane (PU) Latex-Polyelectrolyte Colloid Systems Enabling One-Pot Fabrication of Nonperiodic Structured Mechanoresponsive Smart Windows.

Mechanoresponsive smart windows can modulate optical transparency by mechanical actuation, showing the advantages of low cost, energy efficiency, and chemical stability. To date, mechanoresponsive smart windows are mainly built on periodic nano- or microstructures such as arrays, wrinkles, 3D photonic crystals, and polymeric nanocomposites. However, the production of periodic structures requires multiple and complicated processes, which restricts large-scale manufacturing of mechanoresponsive smart windows for practical application. Here, we report one-pot fabrication of poly methacrylic acid sodium salt (PMANa)/polyurethane (PU) mechanoresponsive smart windows with a nonperiodic naturally occurring microsized structure. The obtained smart windows display a high contrast ratio and stable transparency switching behavior under 80% tensile strain over 1000 cycles and have a large breaking elongation of 820%. It offers a promising platform for designing and fabricating multifunctional optical devices including anticounterfeiting labels and dynamical light gratings.

A facile approach to fabrication of superhydrophilic ultrafiltration membranes with surface-tailored nanoparticles

Abstract A hydrophilic membrane commonly performs better in resisting fouling. But most prevailing polymeric membrane materials are hydrophobic thus prone to be fouled in practical operations. The current study presents a facile strategy for the fabrication of superhydrophilic polyvinylidene fluoride (PVDF) ultrafiltration membranes on the basis of a blending method and a dip-coating technique. A carboxyl-rich substance was firstly blended as an additive in the PVDF membrane matrix during fabrication. The incorporated carboxyl groups acted as anchor sites for the subsequent binding of amine-grafted silica nanoparticles (NPs). After a simple dip-coating operation, the PVDF membrane would be covalently functionalized to be superhydrophilic. Three types of carboxyl-rich additives including poly(methacrylic acid sodium salt), sodium alginate, and ethylenediaminetetraacetic acid (EDTA) were separately used to prepare different primary membranes for respective functionalization operations. The resultant membranes were systematically characterized in terms of hydrophilicity, morphology, permeability, and antifouling performance. Consequently, the simple dip-coating functionalization dramatically enhanced the surface hydrophilicity of all the additive-blended PVDF membranes. All the functionalized membranes obtained a significantly lower initial contact angle, which instantly reduced to

One-pot synthesis of active copper-containing carbon dots with laccase-like activities

Herein, an effective strategy for designing a new type of nanozyme, blue fluorescent laccase mimics, is reported. Active copper-containing carbon dots (Cu-CDs) were synthesized through a simple, nontoxic and one-pot hydrothermal method, which showed favorable photoluminescence properties and good photostability under high-salt conditions or in a broad pH range (3.0-13.5). The Cu-CDs possessed intrinsic laccase-like activities and could catalyze the oxidation of the laccase substrate p-phenylenediamine (PPD) to produce a typical color change from colorless to brown. Poly(methacrylic acid sodium salt) (PMAA) not only was used as the carbon source and reducing agent, but also provided carboxyl groups to assist flocculation between Cu-CDs and polyacrylamide, which facilitated the removal of PPD. Importantly, the intrinsic fluorescence of the as-prepared Cu-CDs could indicate the presence of hydroquinone, one of the substrates of laccases, based on laccase mimics and fluorescence quenching.

Microencapsulation of n-hexadecane phase change material by ethyl cellulose polymer

Microencapsulation of phase change materials (PCMs) is an attractive opportunity for broadening their applications. In this respect, a novel encapsulating polymer, ethyl cellulose (EC) was used to entrap n-hexadecane (HD) PCM by an emulsion-solvent evaporation method. Emulsifiers strongly influenced the size and morphology of the forming EC–HD composite microcapsules, and they also had a great impact on their thermal properties. All of the three emulsifiers were suitable to prepare quasi core–shell microparticles, though the high porosity of shells resulted in serious leakage in composites prepared by Tween 80, and permeability of particles manufactured by poly(vinyl alcohol) (PVA), as can be stated from scanning electron microscopy and differential scanning calorimetry analysis. Interfacial tension measurements and spreading coefficient analysis enabled the prediction of preparation conditions for usable core–shell microcapsules. Volume-weighted mean diameters of the microparticles were 319, 92 and 85 μm formed by Tween 80, PVA and poly(methacrylic acid sodium salt) (PMAA), respectively. A significantly higher HD content and latent heat storage capacity could be achieved using PVA and PMAA than with Tween 80. The thermal cycling test indicated good thermal reliability of microcapsules prepared by PMAA, while the energy-storing capacity of composites prepared by PVA decreased substantially, and a dramatic reduction was found in microparticles using Tween 80.

Properties of electrically responsive hydrogels as a potential dynamic tool for biomedical applications

ABSTRACTHydrogels with electric responsive properties are gaining research focus due to increasing demand for miniaturized devices that can be precisely controlled using an external stimulus. Such systems are well suited due to their ability to expand and contract when in contact with different types of fluid. This study reports on the synthesis of a “smart” electroresponsive network, using a neutral, “non‐smart,” biocompatible hydrogel forming building block, Pluronic F127 (PF127), as a starting molecule. The PEO–PPO–PEO copolymer was modified with telechelic methacrylic end functionalities to form a triblock linear prepolymer with crosslinkable end groups (crosslinker). This bifunctional prepolymer, PF127 bismethacrylate (PF127BMA), was copolymerized covalently with anionic methacrylic acid sodium salt groups into a nonsoluble 3D hydrogel network in the presence of redox initiators. The polyelectrolyte domains in the pluronic hydrogel afforded controllable swelling capabilities with volumetric expansion exceeding 8500% in deionized water or 1400% in Krebs solution. The hydrogels were further assessed for their mechanical and electroactive response as a function of increasing acid salt content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41195.

Thermo-responsive gelatin-functionalized PCL film surfaces for improvement of cell adhesion and intelligent recovery of gene-transfected cells

Efficient local gene transfection on a tissue scaffold is dependent on good cell-adhesion characteristics. In this work, the thermo-responsive gelatin-functionalized polycaprolactone (PCL) films were proposed for improvement of cell adhesion and intelligent recovery of gene-transfected cells. Functional copolymer brushes (PCL-g-P(NIPAAm-co-MAAS)) were first prepared via surface-initiated ATRP of N-isopropylacrylamide (NIPAAm) and methacrylic acid sodium salt (MAAS) from the initiator-funcationalized PCL surfaces. The pendant carboxyl end-groups of the PCL-g-P(NIPAAm-co-MAAS) surface were subsequently coupled with gelatin via carbodiimide chemistry to produce the thermo-responsive gelatin-functionalized PCL surface. The thermo-responsive gelatin-functionalized PCL film surface can improve cell adhesion and proliferation above the LCST of P(NIPAAm) without destroying cell detachment properties at lower temperatures. The dense transfected cells can be recovered simply by lowering culture temperature. The thermo-responsive gelatin-functionalized PCL films are potentially useful as intelligent adhesion modifiers for directing cellular functions within tissue scaffolds.

PHEA-graft-polymethacrylate supramolecular aggregates for protein oral delivery

Salmon calcitonin (sCT) is characterized by a poor oral availability. A new copolymer, β-poly(N-2-hydroxyethyl)-graft-{N-2-ethylene[2-poly(methacrylic acid sodium salt)isobutyrate]}-d,l-aspartamide (PHEA-IB-p(MANa+)), was designed for the oral administration of sCT through the formation of supramolecular aggregates (SAs) based on electrostatic interactions. Several sCT/PHEA-IB-p(MANa+) weight ratios were characterized by turbidimetry, DLS, zeta potential, and microscopy analysis. After the incubation of sCT/PHEA-IB-p(MANa+) complex with digestive enzymes, 10% (w/w) of loaded sCT was released in the native form. In vitro investigation was carried out to determine the copolymer effect on the permeability of sCT in Caco-2 cell monolayers. sCT pharmacokinetic profile and the pharmacodynamic effect on calcium plasma level were determined following an oral administration of the lead sCT/PHEA-IB-p(MANa+) SA (1/5 ratio) in rats. The SA yielded a marked prolongation of the sCT lowering calcium effect. The maximum decrease, 35% with respect the basal calcium plasma level at time 0h, was achieved after 4h post-administration, and after 7h, a decrease of 20% was still present. Differently, sCT yielded a transient calcium decrease that was completely restored after 5h. The higher bioavailability of sCT administered as SA was confirmed by the pharmacokinetic studies. In fact, the AUC and the Cmax were about 15 times higher for the sCT formulated as SA than the free sCT. This study indicates the potentials of PHEA-IB-p(MANa+) as carrier of sCT for oral delivery.

PH‐sensitive drug delivery systems by radical polymerization of gelatin derivatives

AbstractThe objective of this article was the synthesis and characterization of protein‐based microspheres able to respond to pH changes using methacrylated gelatin hydrolyzed, methacrylic acid sodium salt and N,N′‐methylenebisacrylamide as protein monomer, pH‐responsive functional monomer, and cross‐linking agent, respectively. Reverse‐phase suspension polymerization as synthetic technique was adopted and, varying the molar ratios of the reagents in the polymerization feed, three different hydrogels were obtained. These were characterized by scanning electron microscopy and dimensional analyses to verify the spherical shape and the dimensional distribution. Then, Fourier transform infrared spectra and water uptake experiments at acidic and neutral pH were performed, in order to verify the copolymerization of all the components and the pH‐responsivity, respectively. Finally, after loading of the microspheres with a common nonsteroidal anti‐inflammatory drug, such as diclofenac sodium salt, drug release experiments in simulated gastric fluid (pH 1) and in simulated intestinal fluid (pH 7) were performed, confirming the suitability of the obtained materials as drug delivery devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Nanoparticle Modification by Weak Polyelectrolytes for pH-Sensitive Pickering Emulsions

The affinity of weak polyelectrolyte coated oxide particles to the oil-water interface can be controlled by the degree of dissociation and the thickness of the weak polyelectrolyte layer. Thereby the oil in water (o/w) emulsification ability of the particles can be enabled. We selected the weak polyacid poly(methacrylic acid sodium salt) and the weak polybase poly(allylamine hydrochloride) for the surface modification of oppositely charged alumina and silica colloids, respectively. The isoelectric point and the pH range of colloidal stability of both particle-polyelectrolyte composites depend on the thickness of the weak polyelectrolyte layer. The pH-dependent wettability of a weak polyelectrolyte-coated oxide surface is characterized by contact angle measurements. The o/w emulsification properties of both particles for the nonpolar oil dodecane and the more polar oil diethylphthalate are investigated by measurements of the droplet size distributions. Highly stable emulsions can be obtained when the degree of dissociation of the weak polyelectrolyte is below 80%. Here the average droplet size depends on the degree of dissociation, and a minimum can be found when 15 to 45% of the monomer units are dissociated. The thickness of the adsorbed polyelectrolyte layer strongly influences the droplet size of dodecane/water emulsion droplets but has a less pronounced impact on the diethylphthalate/water droplets. We explain the dependency of the droplet size on the emulsion pH value and the polyelectrolyte coating thickness with arguments based on the particle-wetting properties, the particle aggregation state, and the oil phase polarity. Cryo-SEM visualization shows that the regularity of the densely packed particles on the oil-water interface correlates with the degree of dissociation of the corresponding polyelectrolyte.

Silk-functionalized titanium surfaces for enhancing osteoblast functions and reducing bacterial adhesion

It would be ideal to have implants which can simultaneously inhibit bacterial adhesion and promote osteoblast functions. In this work, titanium surfaces were modified with poly(methacrylic acid) (P(MAA)) followed by immobilization of silk sericin. Firstly a trichlorosilane coupling agent, which is an atom transfer radical polymerization (ATRP) initiator, was immobilized on the oxidized titanium surface to facilitate the surface-initiated ATRP of methacrylic acid sodium salt (MAAS). The pendant carboxyl end groups of the grafted and partially protonated MAA chains were subsequently coupled with silk sericin via carbodiimide chemistry. The functionalized Ti surfaces were characterized by X-ray photoelectron spectroscopy, and assayed for osteoblast cell functions and bacterial adhesion. The covalently immobilized MAA brushes significantly reduce the adhesion of the two bacterial strains ( Staphylococcus aureus and Staphylococcus epidermidis) tested. The silk sericin-immobilized surfaces, at the same time, promote osteoblast cells' adhesion, proliferation, and alkaline phosphatase activity. Thus, the P(MAA) and silk sericin functionalized Ti surfaces have potential applications combating biomaterial-centered infection and promoting osseointegration.

PH-Sensitive hydrogels based on bovine serum albumin for oral drug delivery

pH-Sensitive bovine serum albumin (BSA) hydrophilic microspheres were prepared by free radical polymerization of methacrylate derivatized BSA and methacrylic acid sodium salt. Incorporation of both monomers in hydrogels was confirmed by Fourier transform infrared spectroscopy. Morphological analysis by scanning electron microscopy showed spherical shape and porous surface of all prepared samples. The microspheres showed high water affinity at neutral pH values and a narrow dimensional distribution. Network density of hydrogels depends on derivatization degree (DD%) of BSA and/or concentration of modified BSA in the polymerization feed. In order to employ the prepared samples such as pH-sensitive hydrogels, in vitro release studies, in media simulating biological fluids, were performed using diflunisal (DF) and β-propranolol (PR) as model drugs. Experimental data showed that the release profiles depend on drug–matrix interactions and diffusional limitation awardable to crosslinking degree of microparticles. β-Propranolol is quickly released at pH 1.0 and a complete release after 1 h at pH 6.8 was observed. In the case of diflunisal pH-sensitive release was observed. At pH 1.0 low amounts of drug were released (w/w < 10% after 2 h). When the pH is 6.8, the diflunisal release increased in the amount (w/w > 75% after 24 h).